Where does gelatin actually come from? Over 400 million boxes of Jell-O are sold every year, yet no one seems to know what the stuff is made of. Horse hooves? Pig ears? Roasted toenails? Vegetarians and meat-eaters alike, you deserve to know. (Caution: you will get details).

Contrary to many schoolhouse playground stories, gelatin does not come from horse hooves—it’s not far off, though. Hooves are made of keratin, the same stuff our hair and nails are made of. But gelatin comes from collagen, the soft protein that connects our skin, bones, muscles, tendons. It’s the stuff that gets pumped into one’s face to reduce wrinkles, puff up the lips, and basically look like Miss Jolie. And it’s that same quality of bounce, spring and elasticity collagen possesses that makes gelatin the primo stuff for certain food products: jelled fruits, pudding, dairy products, candies and more.

Where does this collagen come from that will eventually become gelatin? Not horse hooves, but certainly pig ears. And bones. And hides. And skins.

“The raw materials used in the production of gelatin are from healthy animals and include cattle bone, cattle hides and fresh, frozen pigskins. In the North American market, these raw materials are basically sourced from government-inspected meat processing facilities.”

Read: the collagen comes from animals in slaughterhouses.

If you have the curiosity (and stomach) to learn the literal process of how gelatin is produced from animals, read on.

2) Animal parts are washed and degreased to get rid of as much fat as possible (yah, I don’t want floating fat in my Jell-O, thanks). Pieces are then roasted to dry out.

3) Pieces are soaked in a strong acid solution for several days to bring out all the minerals and bacteria from the pieces, and it releases the full collagen content.

4) Pieces are then boiled again, the gelatin is extracted, and it is flash-heated for sterilization.

5) Gelatin now passes through machines that press it into sheets, and it is dyed, colored and given any other treatments to make it look and taste like a typical boxed food product.

It’s a mixed bag, this gelatin stuff. Some vegetarians avoid anything made with gelatin because it comes from animals and “supports” slaughterhouses. Others believe that we’re at least using all the animal and utilizing what would otherwise be garbage, waste—so that’s a good thing.

Whatever your stance, you can skip to the playground confidently with your recess buddies and proclaim: “I know where it comes from!!!”